I've used oldmkvi's staccato dot and line-dot suggestion, both with hidden and visible accents.

To shorten a note's duration, select the note(s), and then bring up the MIDI Tool. Click "Note Durations," and then "Percent Alter." Enter a number. See if that works. I use this technique so often that I've created FinaleScripts for 95%, 90%, and 85%. I most often invoke this script for phrasing purposes in playback.

I'm able to create mute and unmute expressions to dampen the Chime in v26, but when exported to 2012, it fails to work properly in 2012 as it does in v26. Unfortunately some things work differently in newer versions so testing needs to be done in 2012.

Zuill

Windows 7, Finale 2011-v26.2
"When all is said and done, more is said than done."

The hidden staccato option works for me in a new document, but only if "Play Finale through MIDI" is selected. I cannot get dynamics, hairpins, staccatos or a created expression set at key velocity of 0 to work in playback when "Play through VST "is selected. As Zuill notes, gogreen's more comprehensive option does not work in v2012. I will upgrade when the next version is released.

Along the lines of hidden staccato notes, you might also copy the staccato mark and then redefine it to a shorter or longer length. I've done this, both hiding and showing the mark. This can be time-consuming in a large score with many staves requiring the adjustment.

I don't know why it's not playing back for you. These changes play back fine for me when "Play through VST" is selected.

The mute and unmute expression option works for me, even letting me adjust key velocity. But the option only works if Finale Play through MIDI is selected. I tried adding the expression in a New Document and Default Document as well as using the Wizard to create a document. Version 2012 apparently does not let me apply any of the options mentioned when Chimes is the instrument, played through MIDI.